I created a PDF using PrinceXML. As far as I know, there is nothing unusual about it. However, text search does not work in many PDF readers, including Mac OS X Preview, and Skim. It does seem to work in some readers.

Any ideas, any similar problems?

Could you email me (mikeday@yeslogic.com) a PDF that demonstrates the problem? Also, does it only affect english text, or text in other non-Latin scripts?